Dibenzoxaphosphorin compounds
AssigneeCiba-Geigy Corporation
InventorsPaul Tschopp, David G. Leppard
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Abstract
Photographic material containing magenta coupler is stabilized by incorporating a dibenzoxaphosphorin of the formula ##STR1## into the emulsion layer containing the coupler or into an adjoining colloid layer. The yellowing on dark storage of such material is substantially reduced as a result. The symbols A and n are defined in claim 1.
Claims1
A compound of the formula ##STR49## wherein A is a group of the formula ##STR50## in which R.sub.12 and R.sub.13 are each a group of the formula ##STR51## wherein X is C.sub.2 -C.sub.8 -alkylene and Y is a OR.sub.4 or --N(R.sub.5)(R.sub.6) group wherein R.sub.4 is C.sub.1 -C.sub.18 -alkyl which is uninterrupted or interrupted one or more times by --O-- or is phenyl or benzyl, R.sub.5 and R.sub.6, independently of each other, are each hydrogen, C.sub.1 -C.sub.18 alkyl, phenyl, benzyl or a --(CH.sub.2).sub.m --O--R.sub.8 group wherein R.sub.8 is C.sub.1 -C.sub.18 -alkyl and m is a number between 1 and 4.
Dependencies are inferred from the claim text.